Hi, turnheath,
The two songs that are "protected and unavailable" are, as QuickTimeKirk says, likely to be iTunes songs. As DRM protected songs they would not be available to use in iMovie and would not be displayed in the audio iTunes sidebar. So any song that you inserted from the display in the audio iTunes sidebar would be available and usable and would not be a cause of your export issue.
If you want to double check, open your iTunes app and select View/View Options in the menu. In the View Options box that appears, under the "File" heading check the box that says "Kind". Then go to your iTunes library. There now should be a column labeled "Kind" that lists which songs are protected and which are not. (You may have to close and reopen your iTunes library.)

I don't think that the song unavailability issue is causing your export problem. Can you provide more details about your export issue? What steps are you taking to export your project and what happens after each step? Are you getting any error messages and if so what are their exact wording?
-- Rich